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Proof of work and slow starts on the Torzon market link
Under heavy load, a short wait can be a sign of defence rather than failure.
The problem it solves
Floods of fake connection requests can overwhelm an onion service. Proof of work makes each request cost a little computing effort.
What you notice
During an attack Tor Browser may spend a few extra seconds before the page appears. The puzzle is solved automatically in the background.
Keep Tor Browser updated
The defence works best with current versions. An outdated browser may wait longer or fail to connect to the torzon market link during floods.
Not the same as a captcha
A built-in proof-of-work delay never asks you to type anything. A page that asks for credentials while you wait is something else.
A short automatic delay can be the onion service defending itself; keep Tor Browser up to date.